Complete Chemistry notes on Metals and Non-metals for BPSC and Other Competitive Exams in 2025
General Science- 11 (Chemistry)
Here’s a detailed explanation of Metals and Non-metals.
Metals and Non-Metals
Elements are broadly classified into metals, non-metals, and metalloids based on their physical and chemical properties. This classification is crucial for understanding their behavior and applications.
1. Physical Properties
These are characteristics that can be observed or measured without changing the chemical identity of the substance.
A. Physical Properties of Metals
Metals are typically found on the left and central parts of the Periodic Table.
- Lustrous (Shiny): Metals have a characteristic shine or metallic luster due to the presence of free electrons that reflect light.
- Example: Gold, silver, copper.
- Malleable: Metals can be hammered or beaten into thin sheets without breaking. This property allows for the fabrication of various metal objects.
- Example: Gold and silver are highly malleable. Aluminum foil is another common example.
- Ductile: Metals can be drawn into thin wires.
- Example: Copper wires are extensively used in electrical wiring. Gold is the most ductile metal.
- Good Conductors of Heat and Electricity: This is also due to the presence of free electrons, which can easily transfer thermal and electrical energy.
- Example: Copper and aluminum are excellent conductors.
- State at Room Temperature: Most metals are solid at room temperature.
- Exception: Mercury (Hg) is a liquid at room temperature.
- Hardness: Most metals are hard.
- Exceptions: Sodium (Na) and Potassium (K) are soft metals that can be cut with a knife.
- High Melting and Boiling Points: Metals generally have high melting and boiling points due to strong metallic bonds.
- Exceptions: Sodium, Potassium, Gallium (Ga), Cesium (Cs), and Mercury have relatively low melting points.
- Sonorous: Metals produce a ringing sound when struck. This property is utilized in bells.
B. Physical Properties of Non-metals
Non-metals are typically found on the right side of the Periodic Table.
- Non-lustrous (Dull): Non-metals generally have a dull appearance.
- Exception: Iodine is a non-metal that has a lustrous, shiny appearance. Diamond (an allotrope of Carbon) is also lustrous.
- Brittle: Non-metals are non-malleable and non-ductile. Solid non-metals are brittle and break into pieces when hammered or stretched.
- Poor Conductors of Heat and Electricity (Insulators): Non-metals generally do not conduct heat or electricity well.
- Exception: Graphite (an allotrope of Carbon) is a good conductor of electricity.
- State at Room Temperature: Non-metals exist in all three states at room temperature.
- Solids: Carbon (C), Sulfur (S), Phosphorus (P), Iodine (I).
- Liquids: Bromine (Br).
- Gases: Oxygen (O2), Nitrogen (N2), Hydrogen (H2), Chlorine (Cl2).
- Softness: Most solid non-metals are soft.
- Exception: Diamond (an allotrope of Carbon) is the hardest natural substance known.
- Low Melting and Boiling Points: Non-metals generally have low melting and boiling points compared to metals.
- Non-sonorous: Non-metals do not produce a ringing sound when struck.
2. Chemical Properties
These properties describe how substances react with other substances or change their chemical composition.
A. Chemical Properties of Metals
Metals have a tendency to lose electrons from their outermost shell to achieve a stable electron configuration, thus forming positive ions (cations). They are generally electropositive.
- Reaction with Oxygen:
- Metals react with oxygen to form metal oxides. These oxides are generally basic in nature, meaning they react with water to form bases or with acids to form salt and water.
- Equation: Metal + Oxygen → Metal Oxide
- Examples:
- 2Mg(s)+O2(g)→2MgO(s) (Magnesium oxide, basic)
- 4Na(s)+O2(g)→2Na2O(s) (Sodium oxide, basic)
- Amphoteric Oxides: Some metal oxides, like aluminum oxide (Al2O3) and zinc oxide (ZnO), show both acidic and basic properties. They react with both acids and bases.
- Example (Aluminium oxide with acid): Al2O3(s)+6HCl(aq)→2AlCl3(aq)+3H2O(l)
- Example (Aluminium oxide with base): Al2O3(s)+2NaOH(aq)→2NaAlO2(aq)+H2O(l) (Sodium aluminate)
- Reaction with Water:
- Metals react with water to form metal oxides/hydroxides and hydrogen gas. The reactivity varies:
- Highly Reactive Metals (K, Na, Ca): React vigorously with cold water.
- Example: 2Na(s)+2H2O(l)→2NaOH(aq)+H2(g)+Heat
- Moderately Reactive Metals (Mg, Al, Zn, Fe): React with steam or hot water (Mg).
- Example: 3Fe(s)+4H2O(steam)→Fe3O4(s)+4H2(g)
- Less Reactive Metals (Pb, Cu, Ag, Au): Do not react with water or steam.
- Highly Reactive Metals (K, Na, Ca): React vigorously with cold water.
- Metals react with water to form metal oxides/hydroxides and hydrogen gas. The reactivity varies:
- Reaction with Acids (Dilute):
- Active metals react with dilute acids to produce a salt and hydrogen gas.
- Equation: Metal + Dilute Acid → Salt + Hydrogen gas
- Examples:
- Zn(s)+2HCl(aq)→ZnCl2(aq)+H2(g)
- Mg(s)+H2SO4(aq)→MgSO4(aq)+H2(g)
- Metals below hydrogen in the reactivity series (like Cu, Ag, Au) do not displace hydrogen from acids.
- Reaction with Salt Solutions (Displacement Reactions):
- A more reactive metal can displace a less reactive metal from its salt solution. This is governed by the Reactivity Series (Activity Series) of metals.
- Reactivity Series (most reactive to least reactive): K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au
- Example: Fe(s)+CuSO4(aq)→FeSO4(aq)+Cu(s) (Iron is more reactive than copper)
- Example (No Reaction): Cu(s)+FeSO4(aq)→No Reaction (Copper is less reactive than iron)
B. Chemical Properties of Non-metals
Non-metals tend to gain or share electrons to complete their outermost shell, forming negative ions (anions) or covalent compounds. They are generally electronegative.
- Reaction with Oxygen:
- Non-metals react with oxygen to form non-metal oxides. These oxides are generally acidic in nature (react with water to form acids or with bases to form salt and water).
- Equation: Non-metal + Oxygen → Non-metal Oxide
- Examples:
- C(s)+O2(g)→CO2(g) (Carbon dioxide, acidic)
- S(s)+O2(g)→SO2(g) (Sulfur dioxide, acidic)
- Neutral Oxides: Some non-metal oxides are neutral, meaning they do not react with acids or bases (e.g., Carbon Monoxide – CO, Nitrous Oxide – N2O, Water – H2O).
- Reaction with Water/Acids:
- Non-metals generally do not react with water or dilute acids.
- Reaction with Salt Solutions:
- More reactive non-metals can displace less reactive non-metals from their salt solutions. For halogens, reactivity decreases down the group (F2>Cl2>Br2>I2).
- Example: Cl2(g)+2NaBr(aq)→2NaCl(aq)+Br2(aq) (Chlorine is more reactive than bromine)
- Reaction with Hydrogen:
- Non-metals react with hydrogen to form hydrides (e.g., N2+3H2→2NH3 (ammonia), H2+Cl2→2HCl).
3. Extraction of Metals (Metallurgy – Basics)
The process of extracting metals from their ores and refining them is called metallurgy. The method used depends on the metal’s reactivity.
- Highly Reactive Metals (K, Na, Ca, Mg, Al): Extracted by electrolytic reduction of their molten chlorides or oxides. Carbon cannot reduce them because they are more reactive than carbon.
- Example: Electrolysis of molten NaCl to get Na metal.
- Moderately Reactive Metals (Zn, Fe, Pb, Cu): Extracted by reduction with carbon (coke) or other reducing agents, after converting their sulfide or carbonate ores to oxides by roasting or calcination.
- Example: ZnO(s)+C(s)heat Zn(s)+CO(g)
- Less Reactive Metals (Ag, Hg, Au, Pt): Often found in free (native) state or easily reduced. Oxides can be reduced by heating alone.
- Example: 2HgO(s)heat 2Hg(l)+O2(g)
4. Important Alloys
An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. Alloys are made to improve specific properties of metals.
- Steel: An alloy of Iron (Fe) and Carbon (C). Stronger and more durable than pure iron. Stainless steel also contains Chromium (Cr) and Nickel (Ni) for corrosion resistance.
- Brass: An alloy of Copper (Cu) and Zinc (Zn). Stronger and more malleable than pure copper, used in utensils, decorative items.
- Bronze: An alloy of Copper (Cu) and Tin (Sn). Harder and more resistant to corrosion than pure copper, used in statues, coins, bells.
- Solder: An alloy of Lead (Pb) and Tin (Sn). Has a low melting point, used for joining metals in electrical work.
- Amalgam: An alloy of Mercury with another metal (e.g., dental amalgam is with silver, tin, copper).
Practice Questions
- Which of the following is a physical property characteristic of most metals?
- A) Brittleness
- B) Dull appearance
- C) Ductility
- D) Poor electrical conductivity
- Rationale: Ductility (ability to be drawn into wires) is a key physical property of metals.
- Which non-metal is an excellent conductor of electricity?
- A) Sulfur
- B) Iodine
- C) Graphite
- D) Phosphorus
- Rationale: Graphite, an allotrope of carbon, is unique among non-metals for its electrical conductivity.
- The only metal that is liquid at room temperature is:
- A) Gold
- B) Silver
- C) Mercury
- D) Copper
- Rationale: Mercury (Hg) is unique for being a liquid metal at standard room temperature.
- Metal oxides are generally:
- A) Acidic
- B) Basic
- C) Neutral
- D) Amphoteric only
- Rationale: Most metal oxides are basic, reacting with water to form bases or with acids to form salt and water. Some are amphoteric, but basic is the general characteristic.
- Which of the following metals reacts vigorously with cold water, producing hydrogen gas?
- A) Iron (Fe)
- B) Magnesium (Mg)
- C) Copper (Cu)
- D) Sodium (Na)
- Rationale: Sodium and Potassium are highly reactive metals that react violently with cold water.
- When a non-metal oxide dissolves in water, the resulting solution is generally:
- A) Basic
- B) Neutral
- C) Acidic
- D) Amphoteric
- Rationale: Non-metal oxides are typically acidic oxides, forming acids when dissolved in water (e.g., CO2+H2O→H2CO3).
- In the reaction Zn(s)+CuSO4(aq)→ZnSO4(aq)+Cu(s), which statement is true?
- A) Copper is more reactive than zinc.
- B) This is a combination reaction.
- C) Zinc displaces copper because zinc is more reactive.
- D) This is a double displacement reaction.
- Rationale: Zinc is higher in the reactivity series than copper, allowing it to displace copper from its sulfate solution. This is a single displacement reaction.
- Which method is used to extract highly reactive metals like Sodium from their ores?
- A) Reduction with carbon
- B) Roasting
- C) Electrolytic reduction
- D) Heating with water
- Rationale: Highly reactive metals cannot be reduced by carbon and require electrolytic reduction of their molten compounds.
- Brass is an alloy primarily composed of:
- A) Copper and Tin
- B) Iron and Carbon
- C) Copper and Zinc
- D) Lead and Tin
- Rationale: Brass is a well-known alloy of copper and zinc.
- The process of converting a sulfide ore into its oxide by heating in the presence of excess air is called:
- A) Calcination
- B) Roasting
- C) Electrolysis
- D) Smelting
- Rationale: Roasting is the process of heating a sulfide ore in the presence of air to convert it to its oxide.
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